'Supernatural' Season 9 Spoilers: Dean Gets Inside Sam's Head, Literally [Video]

"Just because you're dying doesn't mean you're dead. We're gonna fight this."

Those are the words Dean (Jensen Ackles) tells his ailing brother, Sam (Jared Padalecki) in a sneak preview for the upcoming season of "Supernatural." But last season's explosive season finale left Sam comatose. So how is Dean talking to his brother?

He's inside his head. That's right; the elder Winchester brother takes a trip inside his brother's brain to break the news to him that he's dying. Even though he is barely surviving, Dean is determined to save Sam from the cold clutches of the Grim Reaper.

"There ain't no me if there ain't no you," Dean yells at Sam.

The preview also shows Bobby (Jim Beaver) giving some advice, Abaddon (Alaina Huffman) doing some hell raising and Castiel (Misha Collins) offering help to people who really don't want it.

TVLine reports that Jensen Ackles and Jared Padalecki teased that Dean is keeping a secret about why Sam lives, adding to the speculation that Dean makes a deal with the harbinger of death, the grim reaper, to ensure his brother's survival. But the promo also teases that a fallen angel could heal Sam, and perhaps Dean as well.

This season, the fallen angel Castiel will be forced to adapt to life as a mortal after his transformation last season from angel to human. At Comic-Con, Collins joked about Castiel adapting to human life, and pointed out that he can no longer aid the Winchester brothers as he previously did. He joked that "now he [Castiel] can pop in and basically fold laundry. There's a shift in the dynamic there in terms of how he can be utilized by the brothers."

Executive producer Jeremy Carver commented on how the upcoming season will deal with the aftermath of last season's fallen angels.

"A world full of fallen angels is pretty much a free-for-all," Carver said.

"We're going to see it's not one unified body," he added. "We've got lots of angels out there with lots of different agendas. Many are feelings lost and vengeful. A world of fallen angels is a dirty, bloody, scary and, in some ways, a very human world."

As the promo suggests, season nine will focus more on the relationship between the Winchester brothers. While they still have a complicated relationship, this season will see the siblings band together more than ever due to dire circumstances.

Tune into the premiere on the CW on October 8 at 9 p.m. to find out what happens next.